Patent Literature 1 discloses a technology applicable to an engine in which a first operating system (for instance, uniform combustion) on a high-rotation high-load side and a second operating system (for instance, stratified charge combustion) on a low-rotation low-load side which has combustion efficiency higher than the first operating system are carried out by changeover therebetween. When an engine operating range changes from a second operating range in which the second operating system is carried out to a first operating range in which the first operating system is carried out, a reaction force (a pedal effort) relative to a depressing force that is applied to an accelerator pedal is rapidly increased in a stage in which the engine operating range has entered into a boundary operating range immediately before changing to the first operating range. An increment of the pedal effort is cancelled when the engine operating range is returned from the boundary operating range to the second operating range.